<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
    <h1> The Ajax 02 Page</h1>
    <button onclick="doAjaxGet()">Do Ajax Get</button>
    <button onclick="doAjaxPost()">Do Ajax Post</button>
    <button onclick="doAjaxDelete()">Do Ajax Delete</button>
    <button onclick="doAjaxUpdate()">Do Ajax Update</button>
    <div id="result"></div>
<script>
    function doAjaxGet() {
        let xhr=new XMLHttpRequest();
        xhr.onreadystatechange=function () {
            if(xhr.readyState==4&&xhr.status==200){
                document.getElementById("result").innerHTML=xhr.responseText;
            }
        }
        xhr.open("GET","http://localhost/doAjaxGet",true)
        xhr.send(null);//可以null，也可以不传
    }

    function doAjaxPost() {
        let xhr=new XMLHttpRequest();
        xhr.onreadystatechange=function () {
            if(xhr.readyState==4&&xhr.status==200){
                document.getElementById("result").innerHTML=xhr.responseText;
            }
        }
        xhr.open("POST","http://localhost/doAjaxPost",true);
        xhr.setRequestHeader("Content-Type",
        "application/x-www-form-urlencoded");
        xhr.send("id=101&name=computer&remark=computer...");//可以null，也可以不传
    }

    function doAjaxDelete() {
        let xhr=new XMLHttpRequest();
        xhr.onreadystatechange=function () {
            if(xhr.readyState==4&&xhr.status==200){
                document.getElementById("result").innerHTML=xhr.responseText;
            }
        }
        xhr.open("delete","http://localhost/doAjaxDelete?id=101",true)
        xhr.send(null);//可以null，也可以不传
    }

    function doAjaxUpdate() {
        let xhr=new XMLHttpRequest();
        xhr.onreadystatechange=function () {
            if(xhr.readyState==4&&xhr.status==200){
                document.getElementById("result").innerHTML=xhr.responseText;
            }
        }
        xhr.open("put","http://localhost/doAjaxUpdate?id=101&name=Boot&remark=Boot...",true)
        xhr.send(null);//可以null，也可以不传
    }

    // function doAjaxUpdate() {
    //     let xhr=new XMLHttpRequest();
    //     xhr.onreadystatechange=function () {
    //         if(xhr.readyState==4&&xhr.status==200){
    //             document.getElementById("result").innerHTML=xhr.responseText;
    //         }
    //     }
    //     xhr.open("put","http://localhost/doAjaxUpdate",true);
    //     xhr.setRequestHeader("Content-Type",
    //         "application/x-www-form-urlencoded");
    //     xhr.send("id=101&name=Boot&remark=Boot...");//可以null，也可以不传
    // }

</script>
</body>
</html>